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LibGfx/OpenType: Extract for_each_table_record() helper

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Separates table record iteration from doing something with the table
records, which is arguably easier to read.

No behavior change.
This commit is contained in:
Nico Weber 2024-02-28 08:12:09 -05:00 • committed by Tim Flynn
parent 953573565c
commit 93038f6f24
1 changed files with 54 additions and 45 deletions
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99
Userland/Libraries/LibGfx/Font/OpenType/Font.cpp
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@ -183,13 +183,31 @@ ErrorOr<NonnullRefPtr<Font>> Font::try_load_from_externally_owned_memory(Readonl
return try_load_from_offset(buffer, 0, move(options)); return try_load_from_offset(buffer, 0, move(options));
} }
// FIXME: "loca" and "glyf" are not available for CFF fonts. static ErrorOr<void> for_each_table_record(ReadonlyBytes buffer, u32 offset, Function<ErrorOr<void>(Tag, ReadonlyBytes)> callback)
ErrorOr<NonnullRefPtr<Font>> Font::try_load_from_offset(ReadonlyBytes buffer, u32 offset, Options options)
{ {
FixedMemoryStream stream { buffer }; FixedMemoryStream stream { buffer };
TRY(stream.seek(offset, AK::SeekMode::SetPosition)); TRY(stream.seek(offset, AK::SeekMode::SetPosition));
auto& table_directory = *TRY(stream.read_in_place<TableDirectory const>());
auto& table_directory = *TRY(stream.read_in_place<TableDirectory const>());
for (auto i = 0; i < table_directory.num_tables; i++) {
auto& table_record = *TRY(stream.read_in_place<TableRecord const>());
if (Checked<u32>::addition_would_overflow(static_cast<u32>(table_record.offset), static_cast<u32>(table_record.length)))
return Error::from_string_literal("Invalid table offset or length in font");
if (buffer.size() < table_record.offset + table_record.length)
return Error::from_string_literal("Font file too small");
auto buffer_here = buffer.slice(table_record.offset, table_record.length);
TRY(callback(table_record.table_tag, buffer_here));
}
return {};
}
// FIXME: "loca" and "glyf" are not available for CFF fonts.
ErrorOr<NonnullRefPtr<Font>> Font::try_load_from_offset(ReadonlyBytes buffer, u32 offset, Options options)
{
Optional<ReadonlyBytes> opt_head_slice = {}; Optional<ReadonlyBytes> opt_head_slice = {};
Optional<ReadonlyBytes> opt_name_slice = {}; Optional<ReadonlyBytes> opt_name_slice = {};
Optional<ReadonlyBytes> opt_hhea_slice = {}; Optional<ReadonlyBytes> opt_hhea_slice = {};
@ -207,50 +225,41 @@ ErrorOr<NonnullRefPtr<Font>> Font::try_load_from_offset(ReadonlyBytes buffer, u3
Optional<CBDT> cbdt; Optional<CBDT> cbdt;
Optional<GPOS> gpos; Optional<GPOS> gpos;
for (auto i = 0; i < table_directory.num_tables; i++) { TRY(for_each_table_record(buffer, offset, [&](Tag table_tag, ReadonlyBytes tag_buffer) -> ErrorOr<void> {
auto& table_record = *TRY(stream.read_in_place<TableRecord const>());
if (Checked<u32>::addition_would_overflow(static_cast<u32>(table_record.offset), static_cast<u32>(table_record.length)))
return Error::from_string_literal("Invalid table offset or length in font");
if (buffer.size() < table_record.offset + table_record.length)
return Error::from_string_literal("Font file too small");
auto buffer_here = buffer.slice(table_record.offset, table_record.length);
// Get the table offsets we need. // Get the table offsets we need.
if (table_record.table_tag == Tag("head")) { if (table_tag == Tag("head")) {
opt_head_slice = buffer_here; opt_head_slice = tag_buffer;
} else if (table_record.table_tag == Tag("name")) { } else if (table_tag == Tag("name")) {
opt_name_slice = buffer_here; opt_name_slice = tag_buffer;
} else if (table_record.table_tag == Tag("hhea")) { } else if (table_tag == Tag("hhea")) {
opt_hhea_slice = buffer_here; opt_hhea_slice = tag_buffer;
} else if (table_record.table_tag == Tag("maxp")) { } else if (table_tag == Tag("maxp")) {
opt_maxp_slice = buffer_here; opt_maxp_slice = tag_buffer;
} else if (table_record.table_tag == Tag("hmtx")) { } else if (table_tag == Tag("hmtx")) {
opt_hmtx_slice = buffer_here; opt_hmtx_slice = tag_buffer;
} else if (table_record.table_tag == Tag("cmap")) { } else if (table_tag == Tag("cmap")) {
opt_cmap_slice = buffer_here; opt_cmap_slice = tag_buffer;
} else if (table_record.table_tag == Tag("loca")) { } else if (table_tag == Tag("loca")) {
opt_loca_slice = buffer_here; opt_loca_slice = tag_buffer;
} else if (table_record.table_tag == Tag("glyf")) { } else if (table_tag == Tag("glyf")) {
opt_glyf_slice = buffer_here; opt_glyf_slice = tag_buffer;
} else if (table_record.table_tag == Tag("OS/2")) { } else if (table_tag == Tag("OS/2")) {
opt_os2_slice = buffer_here; opt_os2_slice = tag_buffer;
} else if (table_record.table_tag == Tag("kern")) { } else if (table_tag == Tag("kern")) {
opt_kern_slice = buffer_here; opt_kern_slice = tag_buffer;
} else if (table_record.table_tag == Tag("fpgm")) { } else if (table_tag == Tag("fpgm")) {
opt_fpgm_slice = buffer_here; opt_fpgm_slice = tag_buffer;
} else if (table_record.table_tag == Tag("prep")) { } else if (table_tag == Tag("prep")) {
opt_prep_slice = buffer_here; opt_prep_slice = tag_buffer;
} else if (table_record.table_tag == Tag("CBLC")) { } else if (table_tag == Tag("CBLC")) {
cblc = TRY(CBLC::from_slice(buffer_here)); cblc = TRY(CBLC::from_slice(tag_buffer));
} else if (table_record.table_tag == Tag("CBDT")) { } else if (table_tag == Tag("CBDT")) {
cbdt = TRY(CBDT::from_slice(buffer_here)); cbdt = TRY(CBDT::from_slice(tag_buffer));
} else if (table_record.table_tag == Tag("GPOS")) { } else if (table_tag == Tag("GPOS")) {
gpos = TRY(GPOS::from_slice(buffer_here)); gpos = TRY(GPOS::from_slice(tag_buffer));
}
} }
return {};
}));
if (!opt_head_slice.has_value()) if (!opt_head_slice.has_value())
return Error::from_string_literal("Font is missing Head"); return Error::from_string_literal("Font is missing Head");